Compact Folders Now and Then in Mozilla Thunderbird, Netscape or Mozilla

When you delete a message in Mozilla Thunderbird, Netscape or Mozilla, it is not immediately physically removed from the mailbox file but only hidden from display. This speeds up things considerably, but it also wastes valuable hard disk space.

Compact Folders Now and Then in Mozilla Thunderbird, Netscape or Mozilla

To reclaim that space for the current account and compact folders in Mozilla Thunderbird, Netscape or Mozilla:

• Select File | Compact Folders from the menu.

If your folders are big and you have deleted lots of (large) messages since the last compacting, this can take some time.